91 of the ESS glossary’s terms, each with the part of the syllabus where you first meet it.
Discarded electrical and electronic equipment, such as phones, computers and batteries, which contains valuable metals and hazardous substances such as lead, mercury and brominated flame retardants.
The planet viewed as a single integrated system in which the biosphere, hydrosphere, cryosphere, geosphere, atmosphere and anthroposphere are linked by flows of energy and matter.
The degree to which the Earth’s orbit around the Sun departs from a circle; one of the Milankovitch cycles, varying over periods of about 100,000 and 405,000 years.
A label on a product showing that it meets an independent standard for environmental sustainability, such as seafood from a fishery certified as well managed.
An environmental perspective that gives the natural world pre-eminent importance and intrinsic value, putting ecological processes and all living things ahead of human wants.
The outer boundary of the doughnut economics model, based on the planetary boundaries, beyond which human pressure overshoots the Earth's life-supporting systems.
An approach to economics that treats the economy as a subsystem of society and of the finite biosphere, and aims to keep its scale within the limits of natural systems.
The percentage of the energy received by one trophic level that is passed on to the next; typically 10% or less, but it varies between ecosystems, levels and species.
The area of land and water required to sustainably provide all the resources a population consumes and absorb all the wastes it produces, at its current rates; measured in global hectares.
Reproductive isolation in which populations in the same area use different habitats, food sources or hosts, so they rarely meet to mate.
The situation in which a population's ecological footprint exceeds the biocapacity available to it, so that natural capital is depleted and wastes accumulate.
A diagram of stacked horizontal bars, one per trophic level, whose widths show the relative numbers, biomass or energy at each level.
The process of helping a degraded, damaged or destroyed ecosystem recover, for example by replanting native species, removing invasive species or restoring natural water flows.
A holistic approach to planning that treats the urban system as an ecosystem, designing land use, buildings and infrastructure around the relationships between people, other organisms and the abiotic environment.
The growing integration of national economies through international trade, investment and supply chains, which increases supply of resources but also interdependence between countries.
The change in the total market value of the goods and services produced in a country over a period, usually measured as the annual percentage change in GDP.
The maintenance of economic structures and systems that support the production and consumption of goods and services to meet human needs into the future.
The worth of natural capital that can be traded or measured in money, such as the market price of timber, fish, minerals or farmland.
A shortage of water caused by a lack of investment in storage, treatment and distribution, or by a lack of human capacity, even though enough freshwater exists naturally.
The study of how individuals and societies produce, distribute and consume goods and services, and how they allocate limited resources between competing uses.
A protected area surrounded by a pest-exclusion fence, inside which introduced predators are removed so that native species can be reintroduced and recover.
A community of interdependent organisms and the physical environment with which it interacts.
A change in which an ecosystem loses its defining species, structure or functions and shifts to a different, usually less valuable state from which recovery is slow or impossible.
An organism that creates, modifies or maintains habitat by changing the physical environment, such as beavers building dams or elephants pushing over trees.
The extent to which an ecosystem keeps its natural structure, species composition and processes, such as nutrient cycling, so that it can function and recover from disturbance.
The benefits that ecosystems provide to people and other living things, grouped as provisioning, regulating, cultural and supporting services, such as food, flood control, recreation and nutrient cycling.
A transition zone between two communities or biomes, where species from both occur and the community changes along an environmental gradient.
Responsible travel to natural areas that conserves the environment, sustains the well-being of local people and involves education, with income that can help fund protection.
The changes in conditions and species at the boundary between two habitats, such as more light, wind, predators and invasive species at the edge of a forest reserve than in its interior.
Liquid waste discharged into the environment from a pipe or outfall, such as treated or untreated sewage or industrial wastewater.
The removal from the gut of undigested food that was never absorbed into the body, as faeces.
The warm phase of ENSO, in which the Walker circulation weakens or reverses, warm water spreads east across the tropical Pacific and upwelling off western South America decreases.
The irregular fluctuation in winds and sea-surface temperatures across the tropical Pacific Ocean between El Niño, neutral and La Niña states, which affects weather in many parts of the world.
The full range of electromagnetic radiation, from long-wavelength radio waves through microwaves, infrared, visible light and ultraviolet to short-wavelength X-rays and gamma rays.
A characteristic of a system that arises from the interactions between its components and is not shown by any component on its own.
The number of people leaving an area to live elsewhere, per 1,000 people of the population they leave per year.
A plausible description of how future greenhouse gas and aerosol emissions could develop, based on assumptions about population, economy, technology and policy, used as an input to climate models.
A scheme in which a government caps total emissions, issues permits up to the cap and lets emitters buy and sell them, so that emissions are cut where it is cheapest.
The IUCN Red List category for species facing a very high risk of extinction in the wild, between Vulnerable and Critically Endangered.
A species found naturally in only one place, such as a single island, country or mountain range, and nowhere else in the world.
A chemical that interferes with the production or action of hormones in an organism, disrupting growth, development or reproduction, often at very low concentrations.
A lake in a basin with no outlet to the sea, which loses water only by evaporation and seepage, so dissolved salts build up in it.
Reducing energy consumption by changing behaviour so that less of an energy service is used, such as switching off lights, turning heating down or travelling less.
Using technology to obtain the same energy service, such as light, warmth or transport, from less energy input, for example with LED lighting, insulation or efficient engines.
The one-way movement of energy through an ecosystem, entering mainly as sunlight, passing between trophic levels as chemical energy in food, and leaving as heat.
A systems diagram showing energy entering, passing between and leaving trophic levels, with arrows whose widths are often drawn in proportion to the size of each flow.
The combination of primary energy sources used to meet the energy demand of a country or region, usually expressed as the percentage supplied by each source.
The uninterrupted availability of energy sources at an affordable price; reliable access by a society to enough affordable energy to meet its needs now and in the future.
The capture of energy produced at one time, as chemical, gravitational potential or thermal energy, so that it can be released as electricity or heat later.
The strengthening of the natural greenhouse effect by greenhouse gases added to the atmosphere by human activities, such as burning fossil fuels and farming, which causes global warming.
The digestion of plant material by microorganisms in the gut of ruminant animals, which releases methane that the animals breathe out or belch.
A measure of the disorder of a system and of how spread out its energy is; it increases in every energy transformation as energy is degraded to heat.
The attempt to attach economic values to natural resources, ecosystem services and their depletion, and to include these values in the accounts of businesses or nations.
A person who campaigns publicly, through protest, advocacy, writing or direct action, to change attitudes, behaviour or policy on an environmental issue.
A check made during or after a development project that compares its actual environmental impacts with those predicted and tests whether mitigation and legal conditions are being met.
The inclusion of environmental rights and duties in a country's constitution, such as a right to a healthy environment or rights for nature, so that they rank above ordinary laws.
A branch of economics that applies economic principles to environmental issues, treating environmental damage as a cost to be measured and corrected within the existing market economy.
The branch of ethics that studies the moral relationship between humans and the natural environment, including the moral status of non-human and non-living entities.
The quantity, timing and quality of water flow that must be left in a river, wetland or estuary to sustain its ecosystems and the people who depend on them.
A gradual change in one or more abiotic factors, such as temperature, exposure or soil moisture, across a distance in space.
A process carried out before a development project is approved that identifies and predicts its environmental, social and economic impacts, proposes mitigation, and is followed by monitoring and audits.
The right of all people to live in a pollution-free environment and to have equitable access to natural resources, regardless of race, gender, socio-economic status or nationality.
A hypothesis that environmental degradation rises as income per person grows and then falls once a country is rich enough, giving an inverted U-shaped curve.
The body of rules governing how people use and affect natural resources and the environment, covering resources, pollution, biodiversity and development, with the aim of improving social and ecological sustainability.
The movement of people, temporarily or permanently, within or across borders, mainly because sudden or gradual changes in the environment harm their lives or living conditions.
The broad social and political movement of individuals, groups and organisations that works to protect the natural environment and change human behaviour, policy and law towards it.
The use and management of natural resources in a way that allows resources to be replaced and ecosystems to recover and regenerate, avoiding depletion, pollution and biodiversity loss.
A model of a person's or society's environmental perspective as a system, showing the inputs that shape it (such as education, media and worldviews) and the outputs that result (judgements, choices and actions).
A state of balance in a system, in which opposing flows or processes cancel out so that there is no overall change in the system.
The long-term rise in global mean surface temperature once the climate has fully adjusted to a doubling of atmospheric carbon dioxide; the IPCC's best estimate is 3 °C.
Fairness in the distribution of resources, opportunities, costs and benefits, so that no group is systematically disadvantaged; equitable does not necessarily mean equal.
Lines drawn above and below a plotted value, such as a mean, showing its variability or uncertainty, for example one standard deviation either side.
A farmed aquatic animal that has escaped from its cage or pond into the wild, where it may compete with, breed with or spread disease to wild populations.
A structured set of moral principles used to judge whether actions or decisions are right or wrong, such as virtue, consequentialist or rights-based ethics.
The branch of philosophy concerned with moral principles, that is, with which behaviours are right or wrong and how people ought to act.
The enrichment of lakes, estuaries and coastal waters with mineral nutrients, especially nitrates and phosphates, often causing excessive phytoplankton growth and oxygen depletion.
The transformation of liquid water into water vapour, using heat energy mainly from solar radiation; the main flow from the oceans to the atmosphere.
The combined flow of water vapour to the atmosphere by evaporation from soil and water surfaces and by transpiration from plants.
The cumulative change in the heritable characteristics of a population or species over many generations.
Conservation of species outside their natural habitats, for example in zoos, botanic gardens, seed banks and captive-breeding programmes.
A zone of sea extending up to 200 nautical miles (370 km) from a country's coast, in which that country has sovereign rights over fishing and other natural resources under UNCLOS.
The value people place on simply knowing that a species, ecosystem or place exists, even if they never use or visit it.
Growth of a population by a constant proportion in each time period, so that numbers double at regular intervals and the growth curve becomes ever steeper.
The phase of an S-shaped growth curve in which a population grows rapidly and at an increasing rate because resources are plentiful.
A policy approach that makes manufacturers responsible, financially or physically, for collecting and recycling or disposing of their products at the end of their life.
Farming with low inputs of capital, labour or materials per unit area, usually spread over large areas and giving relatively low yields per hectare.
A cost or benefit of producing or consuming a good that falls on a third party not involved in the transaction, who is neither compensated nor charged for it.
The IUCN Red List category for species that survive only in captivity, in cultivation or as populations established outside their natural range.
The permanent disappearance of a species, when its last individual dies.
The number of species that become extinct in a given period, often expressed as extinctions per million species per year and compared with the natural background rate.
A weather event that is rare at a particular place and time of year, such as a heatwave, intense rainfall, drought or tropical cyclone, far outside the usual range of conditions.